Channel integrated optoelectronic tweezer chip for microfluidic particle manipulation

Witte, C. , Reboud, J. , Cooper, J. M. and Neale, S. L. (2020) Channel integrated optoelectronic tweezer chip for microfluidic particle manipulation. Journal of Micromechanics and Microengineering, 30, 045004. (doi: 10.1088/1361-6439/ab6c72)

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Light patterned electrical fields have been widely used for the manipulation of microparticles, from cells to microscopic electronic components. In this work, we explore a novel electromechanical phenomenon for particle focusing and sorting where the electrical field patterns are shaped by a combination of the light patterned photoconductor and the channel geometry. This effect results from the combination of particle polarisation described by the Clausius–Mossotti relation and the engineering of large electric gradients produced by choosing the channels height to suit the size of the particles being manipulated. The matched geometry increases the distortion of the field created by a combination of the illuminated photoconductor and the particles themselves and hence the non-uniformity of the field they experience. We demonstrate a new channel integration strategy which allows the creation of precisely defined channel structures in the OET device. By defining channels in photoresist sandwiched between upper and lower ITO coated glass substrates we produce robust channels of well controlled height tailored to the particle. Uniquely, the top substrate is attached before photolithographically defining the channels. We demonstrate versatile control using this effect with dynamically reconfigurable light patterns allowing the retention against flow, focusing and sorting of micro particles within the channels. Contrary to traditional designs, this channel integrated device allows patterned micro channels to be used in conjunction with conductive top and bottom electrodes producing optimal conditions for the dielectrophoretic manipulation as demonstrated by the rapid flow (up to 5 mm s−1) in which the particles can be focused.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Neale, Professor Steven and Witte, Dr Christian and Cooper, Professor Jonathan and Reboud, Professor Julien
Authors: Witte, C., Reboud, J., Cooper, J. M., and Neale, S. L.
College/School:College of Science and Engineering > School of Engineering > Biomedical Engineering
College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Journal of Micromechanics and Microengineering
Publisher:IOP Publishing
ISSN (Online):1361-6439
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Journal of Micromechanics and Microengineering 30:045004
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
162182Micro-Actuators Controlled by Optoelectronic Tweezers (MACOET)Steven NealeRoyal Academy of Engineering (RAE)EP/G058393/1ENG - Biomedical Engineering